>>A set including the razor body and some heads generally costs a little above £20 and replacement heads cost in the region of £1.75. Gillette claim that each blade can be used for 15 shaves. This sounds pretty optimistic to me. But who knows.
Who knows? I cannot possibly be the only male here who disputes this math. I have a Gillet razor, one with a fancy 5-blade rotating head. It also has a silly vibrator that I am too afraid to use. The blades last forever. Not 15 shaves. More like 150 or more. I have to shave literally every morning, often in a hurry and without shaving cream (military). But I never have any issues. I think that the last time I switched out the blade might have been September of last year when. I had dropped it on concrete and damaged the plastic head. The blades were still fine. The metallurgy behind these things is frankly astonishing.